Wireless communications device with an adjustable impedance matching network and associated methods

Abstract

A mobile wireless communications device includes a portable housing, a transmitter carried by the portable housing and configured to modulate an input signal, and an adjustable impedance matching network coupled downstream from the transmitter. An antenna is coupled downstream from the adjustable impedance matching network, and a non-directional coupler is coupled between the adjustable impedance matching network and the antenna. A feedback receiver is coupled to the non-directional coupler to generate a feedback signal. A controller is configured to control the adjustable impedance matching network based upon the input signal and the feedback signal.

1. A mobile wireless communications device comprising:
 a portable housing; 
 a transmitter carried by said portable housing and configured to modulate an input signal; 
 an adjustable impedance matching network carried by said portable housing and coupled downstream from said transmitter; 
 an antenna carried by said portable housing and coupled downstream from said adjustable impedance matching network; 
 a non-directional coupler carried by said portable housing and coupled between said adjustable impedance matching network and said antenna; 
 a feedback receiver carried by said portable housing and coupled to said non-directional coupler to generate a feedback signal; and 
 a controller carried by said portable housing and configured to control said adjustable impedance matching network based upon the input signal and the feedback signal. 
 
     
     
       2. The wireless communications device according to  claim 1  wherein said non-directional coupler comprises a signal path conductor and a feedback path conductor inductively coupled thereto. 
     
     
       3. The wireless communications device according to  claim 1  wherein said non-directional coupler comprises a signal path conductor and a resistive load coupled thereto. 
     
     
       4. The wireless communications device according to  claim 1  wherein said controller is configured to compare the input signal to the feedback signal in at least one iteration to determine at least one difference therebetween, and adjust an impedance of said adjustable impedance matching based upon the at least one difference. 
     
     
       5. The wireless communications device according to  claim 4  wherein the at least one iteration comprises a plurality of iterations; and wherein said controller is further configured to add a correction value to the input signal in each iteration. 
     
     
       6. The wireless communications device according to  claim 5  wherein said controller is configured to calculate correction values based on a least means square (LMS) algorithm. 
     
     
       7. The wireless communications device according to  claim 4  wherein said controller comprises a delay circuit configured to delay the input signal so that the input signal and the feedback signal match up in time when compared. 
     
     
       8. The wireless communications device according to  claim 7  wherein said delay circuit is configured to implement a fixed delay corresponding to inherent delays of said transmitter and said feedback receiver, and a variable delay corresponding to variable environmental conditions. 
     
     
       9. The wireless communications device according to  claim 1  wherein said adjustable impedance matching network comprises at least one variable capacitor. 
     
     
       10. The wireless communications device according to  claim 1  further comprising a signal receiver carried by said portable housing and coupled to said antenna. 
     
     
       11. The wireless communications device according to  claim 1  wherein said transmitter comprises a multi-frequency band transmitter. 
     
     
       12. A mobile wireless communications device comprising:
 a portable housing; 
 a transceiver carried by said portable housing and configured to operate over a plurality of spaced-apart frequency bands, and comprising a transmitter configured to modulate an input signal within a selected frequency band, and a signal receiver; 
 an adjustable impedance matching network carried by said portable housing and coupled downstream from said transmitter; 
 an antenna carried by said portable housing and coupled to said signal receiver, and coupled downstream from said adjustable impedance matching network; 
 a non-directional coupler carried by said portable housing and coupled between said adjustable impedance matching network and said antenna; 
 a feedback receiver carried by said portable housing and coupled to said non-directional coupler to generate a feedback signal; and 
 a controller carried by said portable housing and configured to compare the input signal to the feedback signal in at least one iteration to determine at least one difference therebetween, and adjust an impedance of said adjustable impedance matching based upon the at least one difference. 
 
     
     
       13. The wireless communications device according to  claim 12  wherein said non-directional coupler comprises a signal path conductor and a feedback path conductor inductively coupled thereto. 
     
     
       14. The wireless communications device according to  claim 12  wherein said non-directional coupler comprises a signal path conductor and a resistive load coupled thereto. 
     
     
       15. The wireless communications device according to  claim 12  wherein the at least one iteration comprises a plurality of iterations; and wherein said controller is further configured to add a correction value to the input signal in each iteration. 
     
     
       16. The wireless communications device according to  claim 12  wherein said adjustable impedance matching network comprises at least one variable capacitor. 
     
     
       17. The wireless communications device according to  claim 12  wherein said transmitter comprises a multi-frequency band transmitter. 
     
     
       18. A method for operating a mobile wireless communications device comprising a transmitter, an adjustable impedance matching network coupled downstream from the transmitter, an antenna coupled downstream from the adjustable impedance matching network, a non-directional coupler coupled between the adjustable impedance matching network and the antenna, and a feedback receiver coupled to the non-directional coupler, the method comprising:
 generating an input signal to be modulated by the transmitter; 
 operating the feedback receiver to generate a feedback signal from the non-directional coupler; and 
 adjusting the adjustable impedance matching network based upon the input signal and the feedback signal. 
 
     
     
       19. The method according to  claim 18  wherein the non-directional coupler comprises a signal path conductor and a feedback path conductor inductively coupled thereto. 
     
     
       20. The method according to  claim 18  wherein the non-directional coupler comprises a signal path conductor and a resistive load coupled thereto. 
     
     
       21. The method according to  claim 18  further comprising comparing the input signal to the feedback signal in at least one iteration to determine at least one difference therebetween; and wherein the adjusting comprises adjusting an impedance of the adjustable impedance matching based upon the at least one difference. 
     
     
       22. The method according to  claim 21  wherein the at least one iteration comprises a plurality of iterations; and further comprising adding a correction value to the input signal in each iteration. 
     
     
       23. The method according to  claim 22  wherein the correction values are calculated based on a least means square (LMS) algorithm. 
     
     
       24. The method according to  claim 21  further comprising delaying the input signal so that the input signal and the feedback signal match up in time when compared. 
     
     
       25. The method according to  claim 24  wherein the delaying comprises a fixed delay corresponding to inherent delays of the transmitter and the feedback receiver, and a variable delay corresponding to variable environmental conditions. 
     
     
       26. The method according to  claim 18  wherein the adjustable impedance matching network comprises at least one variable capacitor. 
     
     
       27. The method according to  claim 18  wherein the mobile wireless communications device comprises a signal receiver coupled to the antenna. 
     
     
       28. The method according to  claim 18  wherein the transmitter comprises a multi-frequency band transmitter.